Conventional hand-operated pipe cutters are conveniently used for cutting installed pipe, but as far as is known no currently available power tool has that capability. Moreover, the use of manual pipe cutters requires, in any event, considerable time and effort.
The broad objects of the present invention are to provide a power-operated pipe cutter, especially a hand-held tool, and a cutting head therefor, which can readily be used to cut pipe and which can reduce significantly the time and effort required to cut both in-place pipe and also separate lengths of material.
Additional objects of the invention are to provide such a pipe cutter and cutting head which are of relatively incomplex construction and which can readily be manufactured at relatively low cost.
It has now been found that certain of the foregoing and related objects of the invention are attained by the provision of a cutting head comprising: a support member having a supporting portion; a mounting member supported by the supporting portion of the support member for rotation about a central axis, the mounting member having at least a first channel extending inwardly from the periphery thereof for permitting lateral insertion of a pipe, for disposition on the central axis of the head; cutting means mounted on the mounting member for rotation therewith and comprising at least two contact elements disposed generally diametrically of the axis and along opposite sides of the first channel, the cutting means being constructed for varying the spacing between the two contact elements so as to permit such lateral insertion of a pipe therebetween and to enable the contact elements to engage opposite sides of a pipe disposed on the central axis, at least one of the contact elements being a cutting element; and a power-transmission arrangement comprising driven means on a peripheral portion of the mounting member and drive means interengaged with the driven means, the power-transmission arrangement including at least one component that effectively spans the entrance to the first channel at the periphery of the mounting member for enabling constant delivery of power to the mounting member.
In certain preferred embodiments the drive means will be constructed to engage the peripheral portion of the mounting member at at least two locations for effecting rotation thereof, the locations being spaced from one another a distance greater than the width of the entrance to the channel in the mounting member. The mounting member will usually comprise at least one substantially circular plate, with the peripheral portion (constituting the driven means) comprising a circumferential marginal portion thereon; the xe2x80x9cat least onexe2x80x9d plate may be a sprocket, and the mounting member may comprise an assembly in which a second plate, attached to the sprocket, mounts the cutting means.
In most instances the driven means will comprise an array of teeth extending along the circumferential marginal portion of the xe2x80x9conexe2x80x9d plate. The cooperating drive means will typically comprise an endless chain disposed to cause a segment thereof, which is longer than the first channel entrance width and which provides the xe2x80x9cat least one component,xe2x80x9d to be in constant engagement with the array of teeth. Alternatively, the drive means may comprise a plurality of gears or pinions providing the xe2x80x9cat least one component,xe2x80x9d one of which gears is disposed at each of the two spaced locations referred to. The drive means may also comprise an endless belt disposed to cause a segment thereof to be in constant driving engagement with the circumferential marginal portion of the xe2x80x9conexe2x80x9d plate, which portion is constructed for driven engagement by the belt segment.
In other preferred embodiments the xe2x80x9cat least one componentxe2x80x9d of the cutting head will comprise a peripheral segment piece that is dimensioned and configured to effectively span the first channel entrance, the mounting member being cooperatively constructed for displaceably positioning the segment piece in such a spanning relationship. The segment piece may for example be sidably mounted on the mounting member, and may comprise a further marginal portion of a substantially circular mounting member when so positioned across the channel entrance.
The cutting means employed in the cutting head will preferably include mounting means comprised of a pair of confronting portions, each supporting at least one contact element, and self-centering adjustment means operatively connected to the confronting portions for varying the spacing between the contact elements, the adjustment means being effective for simultaneously moving the contact elements toward and away from one another through substantially equal distances. Biasing means, acting effectively upon at least one of the contact elements (e.g., the cutting wheel, or a jaw supporting it), will normally serve to urge the diametrically opposed contact elements toward one another.
The confronting portions will usually comprise separate jaws, with the adjustment means advantageously comprising a threaded member having opposite end portions in operative engagement with elements on the jaws for simultaneously moving them in opposite directions. Alternatively, the jaws may have confronting toothed rack portions thereon in operative engagement with a pinion (constituting the adjustment means) rotatably interposed therebetween, again for simultaneously moving the jaws in opposite directions. Means will desirably be provided for causing the adjustment means to operatively engage the support member for advancing and retracting the confronting portions of the mounting means, upon rotation of the mounting member in one or the other direction.
In certain embodiments, the supporting portion of the support member will be constructed for partially surrounding a pipe, and will have at least a second channel extending inwardly from the periphery of the support member for permitting lateral insertion of a pipe thereinto for disposition on the central axis of the head.
Preferably, however, the supporting portion will comprise a forward marginal portion on the support member. In such instances the mounting member may comprise at least one substantially circular plate, the peripheral portion referred to may comprise a circumferential marginal portion of the xe2x80x9cone plate,xe2x80x9d and the supporting portion of the support member may form an arcuate channel constructed to seat and engage the circumferential marginal portion of the one plate of the mounting member.
Other objects of the invention are attained by the provision of a power-operated pipe cutter comprising the cutting head herein described. The cutter will additionally include a body on which the head is disposed, and a motor in operative engagement with the drive means of the power transmission arrangement employed. In most instances the cutter will be integrated for fully portable hand-held use, albeit stand-alone units, to which a separate motor or power pack may be coupled, may also be provided; the tool may be either battery operated or driven by line current. The cutter may or may not include a clutch feature, which can provide additional protection against the stripping of threads, breakage of teeth, etc.